Fix: Use JSON config files for ESM compatibility

- Replace @simpleworkjs/conf with simple custom loader
- Use JSON config files (base, development, production, secrets)
- Add config.js with ESM-compatible deep merge
- Support env var overrides for critical settings
- Auth disabled in dev mode via development.json

package.json

@@ -14,7 +14,6 @@
     "preview": "vite preview"
   },
   "dependencies": {
-    "@simpleworkjs/conf": "^1.0.0",
     "eventsource": "^2.0.2",
     "express": "^4.18.2",
     "express-session": "^1.17.3",